refactor: use GraphQLFeaturesTransport internally

Replace inline GraphQL-Features header logic in bearerAuthTransport with
the exported GraphQLFeaturesTransport. This removes code duplication and
ensures the transport is actually used, not just exported.

Author: SamMorrowDrums

internal/ghmcp/server.go

@@ -99,8 +99,10 @@ func createGitHubClients(cfg MCPServerConfig, apiHost apiHost) (*githubClients,
 	// We use NewEnterpriseClient unconditionally since we already parsed the API host
 	gqlHTTPClient := &http.Client{
 		Transport: &bearerAuthTransport{
-			transport: http.DefaultTransport,
-			token:     cfg.Token,
+			transport: &github.GraphQLFeaturesTransport{
+				Transport: http.DefaultTransport,
+			},
+			token: cfg.Token,
 		},
 	}
 	gqlClient := githubv4.NewEnterpriseClient(apiHost.graphqlURL.String(), gqlHTTPClient)
@@ -639,12 +641,6 @@ type bearerAuthTransport struct {
 func (t *bearerAuthTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 	req = req.Clone(req.Context())
 	req.Header.Set("Authorization", "Bearer "+t.token)
-
-	// Check for GraphQL-Features in context and add header if present
-	if features := github.GetGraphQLFeatures(req.Context()); len(features) > 0 {
-		req.Header.Set("GraphQL-Features", strings.Join(features, ", "))
-	}
-
 	return t.transport.RoundTrip(req)
 }
 

pkg/github/transport.go

@@ -9,9 +9,9 @@ import (
 // header to requests based on context values. This is required for using
 // non-GA GraphQL API features like the agent assignment API.
 //
-// This transport is exported for use by library consumers who need to build
-// their own HTTP clients with GraphQL feature flag support. The MCP server
-// itself uses an inline implementation in its transport stack.
+// This transport is used internally by the MCP server and is also exported
+// for library consumers who need to build their own HTTP clients with
+// GraphQL feature flag support.
 //
 // Usage:
 //